arch/powerpc/include/asm/uaccess.h

   1 #ifndef _ARCH_POWERPC_UACCESS_H
   2 #define _ARCH_POWERPC_UACCESS_H
   3
   4 #ifdef __KERNEL__
   5 #ifndef __ASSEMBLY__
   6
   7 #include <asm/asm-compat.h>
   8 #include <asm/ppc_asm.h>
   9 #include <asm/processor.h>
  10 #include <asm/page.h>
  11
  12 /*
  13  * The fs value determines whether argument validity checking should be
  14  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  15  * get_fs() == KERNEL_DS, checking is bypassed.
  16  *
  17  * For historical reasons, these macros are grossly misnamed.
  18  *
  19  * The fs/ds values are now the highest legal address in the "segment".
  20  * This simplifies the checking in the routines below.
  21  */
  22
  23 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  24
  25 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  26 #ifdef __powerpc64__
  27 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  28 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  29 #else
  30 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  31 #endif
  32
  33 #define get_ds()        (KERNEL_DS)
  34 #define get_fs()        (current->thread.fs)
  35 #define set_fs(val)     (current->thread.fs = (val))
  36
  37 #define segment_eq(a, b)        ((a).seg == (b).seg)
  38
  39 #define user_addr_max() (get_fs().seg)
  40
  41 #ifdef __powerpc64__
  42 /*
  43  * This check is sufficient because there is a large enough
  44  * gap between user addresses and the kernel addresses
  45  */
  46 #define __access_ok(addr, size, segment)        \
  47         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  48
  49 #else
  50
  51 #define __access_ok(addr, size, segment)        \
  52         (((addr) <= (segment).seg) &&           \
  53          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  54
  55 #endif
  56
  57 #define access_ok(type, addr, size)             \
  58         (__chk_user_ptr(addr),                  \
  59          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  60
  61 /*
  62  * The exception table consists of pairs of relative addresses: the first is
  63  * the address of an instruction that is allowed to fault, and the second is
  64  * the address at which the program should continue.  No registers are
  65  * modified, so it is entirely up to the continuation code to figure out what
  66  * to do.
  67  *
  68  * All the routines below use bits of fixup code that are out of line with the
  69  * main instruction path.  This means when everything is well, we don't even
  70  * have to jump over them.  Further, they do not intrude on our cache or tlb
  71  * entries.
  72  */
  73
  74 #define ARCH_HAS_RELATIVE_EXTABLE
  75
  76 struct exception_table_entry {
  77         int insn;
  78         int fixup;
  79 };
  80
  81 static inline unsigned long extable_fixup(const struct exception_table_entry *x)
  82 {
  83         return (unsigned long)&x->fixup + x->fixup;
  84 }
  85
  86 /*
  87  * These are the main single-value transfer routines.  They automatically
  88  * use the right size if we just have the right pointer type.
  89  *
  90  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  91  * and yet we don't want to do any pointers, because that is too much
  92  * of a performance impact. Thus we have a few rather ugly macros here,
  93  * and hide all the ugliness from the user.
  94  *
  95  * The "__xxx" versions of the user access functions are versions that
  96  * do not verify the address space, that must have been done previously
  97  * with a separate "access_ok()" call (this is used when we do multiple
  98  * accesses to the same area of user memory).
  99  *
 100  * As we use the same address space for kernel and user data on the
 101  * PowerPC, we can just do these as direct assignments.  (Of course, the
 102  * exception handling means that it's no longer "just"...)
 103  *
 104  */
 105 #define get_user(x, ptr) \
 106         __get_user_check((x), (ptr), sizeof(*(ptr)))
 107 #define put_user(x, ptr) \
 108         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 109
 110 #define __get_user(x, ptr) \
 111         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 112 #define __put_user(x, ptr) \
 113         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 114
 115 #define __get_user_inatomic(x, ptr) \
 116         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
 117 #define __put_user_inatomic(x, ptr) \
 118         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 119
 120 #define __get_user_unaligned __get_user
 121 #define __put_user_unaligned __put_user
 122
 123 extern long __put_user_bad(void);
 124
 125 /*
 126  * We don't tell gcc that we are accessing memory, but this is OK
 127  * because we do not write to any memory gcc knows about, so there
 128  * are no aliasing issues.
 129  */
 130 #define __put_user_asm(x, addr, err, op)                        \
 131         __asm__ __volatile__(                                   \
 132                 "1:     " op " %1,0(%2) # put_user\n"           \
 133                 "2:\n"                                          \
 134                 ".section .fixup,\"ax\"\n"                      \
 135                 "3:     li %0,%3\n"                             \
 136                 "       b 2b\n"                                 \
 137                 ".previous\n"                                   \
 138                 EX_TABLE(1b, 3b)                                \
 139                 : "=r" (err)                                    \
 140                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 141
 142 #ifdef __powerpc64__
 143 #define __put_user_asm2(x, ptr, retval)                         \
 144           __put_user_asm(x, ptr, retval, "std")
 145 #else /* __powerpc64__ */
 146 #define __put_user_asm2(x, addr, err)                           \
 147         __asm__ __volatile__(                                   \
 148                 "1:     stw %1,0(%2)\n"                         \
 149                 "2:     stw %1+1,4(%2)\n"                       \
 150                 "3:\n"                                          \
 151                 ".section .fixup,\"ax\"\n"                      \
 152                 "4:     li %0,%3\n"                             \
 153                 "       b 3b\n"                                 \
 154                 ".previous\n"                                   \
 155                 EX_TABLE(1b, 4b)                                \
 156                 EX_TABLE(2b, 4b)                                \
 157                 : "=r" (err)                                    \
 158                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 159 #endif /* __powerpc64__ */
 160
 161 #define __put_user_size(x, ptr, size, retval)                   \
 162 do {                                                            \
 163         retval = 0;                                             \
 164         switch (size) {                                         \
 165           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 166           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 167           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 168           case 8: __put_user_asm2(x, ptr, retval); break;       \
 169           default: __put_user_bad();                            \
 170         }                                                       \
 171 } while (0)
 172
 173 #define __put_user_nocheck(x, ptr, size)                        \
 174 ({                                                              \
 175         long __pu_err;                                          \
 176         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 177         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 178                 might_fault();                                  \
 179         __chk_user_ptr(ptr);                                    \
 180         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 181         __pu_err;                                               \
 182 })
 183
 184 #define __put_user_check(x, ptr, size)                                  \
 185 ({                                                                      \
 186         long __pu_err = -EFAULT;                                        \
 187         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 188         might_fault();                                                  \
 189         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 190                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 191         __pu_err;                                                       \
 192 })
 193
 194 #define __put_user_nosleep(x, ptr, size)                        \
 195 ({                                                              \
 196         long __pu_err;                                          \
 197         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 198         __chk_user_ptr(ptr);                                    \
 199         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 200         __pu_err;                                               \
 201 })
 202
 203
 204 extern long __get_user_bad(void);
 205
 206 #define __get_user_asm(x, addr, err, op)                \
 207         __asm__ __volatile__(                           \
 208                 "1:     "op" %1,0(%2)   # get_user\n"   \
 209                 "2:\n"                                  \
 210                 ".section .fixup,\"ax\"\n"              \
 211                 "3:     li %0,%3\n"                     \
 212                 "       li %1,0\n"                      \
 213                 "       b 2b\n"                         \
 214                 ".previous\n"                           \
 215                 EX_TABLE(1b, 3b)                        \
 216                 : "=r" (err), "=r" (x)                  \
 217                 : "b" (addr), "i" (-EFAULT), "0" (err))
 218
 219 #ifdef __powerpc64__
 220 #define __get_user_asm2(x, addr, err)                   \
 221         __get_user_asm(x, addr, err, "ld")
 222 #else /* __powerpc64__ */
 223 #define __get_user_asm2(x, addr, err)                   \
 224         __asm__ __volatile__(                           \
 225                 "1:     lwz %1,0(%2)\n"                 \
 226                 "2:     lwz %1+1,4(%2)\n"               \
 227                 "3:\n"                                  \
 228                 ".section .fixup,\"ax\"\n"              \
 229                 "4:     li %0,%3\n"                     \
 230                 "       li %1,0\n"                      \
 231                 "       li %1+1,0\n"                    \
 232                 "       b 3b\n"                         \
 233                 ".previous\n"                           \
 234                 EX_TABLE(1b, 4b)                        \
 235                 EX_TABLE(2b, 4b)                        \
 236                 : "=r" (err), "=&r" (x)                 \
 237                 : "b" (addr), "i" (-EFAULT), "0" (err))
 238 #endif /* __powerpc64__ */
 239
 240 #define __get_user_size(x, ptr, size, retval)                   \
 241 do {                                                            \
 242         retval = 0;                                             \
 243         __chk_user_ptr(ptr);                                    \
 244         if (size > sizeof(x))                                   \
 245                 (x) = __get_user_bad();                         \
 246         switch (size) {                                         \
 247         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 248         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 249         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 250         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 251         default: (x) = __get_user_bad();                        \
 252         }                                                       \
 253 } while (0)
 254
 255 #define __get_user_nocheck(x, ptr, size)                        \
 256 ({                                                              \
 257         long __gu_err;                                          \
 258         unsigned long __gu_val;                                 \
 259         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 260         __chk_user_ptr(ptr);                                    \
 261         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 262                 might_fault();                                  \
 263         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 264         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 265         __gu_err;                                               \
 266 })
 267
 268 #define __get_user_check(x, ptr, size)                                  \
 269 ({                                                                      \
 270         long __gu_err = -EFAULT;                                        \
 271         unsigned long  __gu_val = 0;                                    \
 272         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 273         might_fault();                                                  \
 274         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 275                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 276         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 277         __gu_err;                                                       \
 278 })
 279
 280 #define __get_user_nosleep(x, ptr, size)                        \
 281 ({                                                              \
 282         long __gu_err;                                          \
 283         unsigned long __gu_val;                                 \
 284         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 285         __chk_user_ptr(ptr);                                    \
 286         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 287         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 288         __gu_err;                                               \
 289 })
 290
 291
 292 /* more complex routines */
 293
 294 extern unsigned long __copy_tofrom_user(void __user *to,
 295                 const void __user *from, unsigned long size);
 296
 297 #ifndef __powerpc64__
 298
 299 static inline unsigned long copy_from_user(void *to,
 300                 const void __user *from, unsigned long n)
 301 {
 302         if (likely(access_ok(VERIFY_READ, from, n))) {
 303                 check_object_size(to, n, false);
 304                 return __copy_tofrom_user((__force void __user *)to, from, n);
 305         }
 306         memset(to, 0, n);
 307         return n;
 308 }
 309
 310 static inline unsigned long copy_to_user(void __user *to,
 311                 const void *from, unsigned long n)
 312 {
 313         if (access_ok(VERIFY_WRITE, to, n)) {
 314                 check_object_size(from, n, true);
 315                 return __copy_tofrom_user(to, (__force void __user *)from, n);
 316         }
 317         return n;
 318 }
 319
 320 #else /* __powerpc64__ */
 321
 322 #define __copy_in_user(to, from, size) \
 323         __copy_tofrom_user((to), (from), (size))
 324
 325 extern unsigned long copy_from_user(void *to, const void __user *from,
 326                                     unsigned long n);
 327 extern unsigned long copy_to_user(void __user *to, const void *from,
 328                                   unsigned long n);
 329 extern unsigned long copy_in_user(void __user *to, const void __user *from,
 330                                   unsigned long n);
 331
 332 #endif /* __powerpc64__ */
 333
 334 static inline unsigned long __copy_from_user_inatomic(void *to,
 335                 const void __user *from, unsigned long n)
 336 {
 337         if (__builtin_constant_p(n) && (n <= 8)) {
 338                 unsigned long ret = 1;
 339
 340                 switch (n) {
 341                 case 1:
 342                         __get_user_size(*(u8 *)to, from, 1, ret);
 343                         break;
 344                 case 2:
 345                         __get_user_size(*(u16 *)to, from, 2, ret);
 346                         break;
 347                 case 4:
 348                         __get_user_size(*(u32 *)to, from, 4, ret);
 349                         break;
 350                 case 8:
 351                         __get_user_size(*(u64 *)to, from, 8, ret);
 352                         break;
 353                 }
 354                 if (ret == 0)
 355                         return 0;
 356         }
 357
 358         check_object_size(to, n, false);
 359
 360         return __copy_tofrom_user((__force void __user *)to, from, n);
 361 }
 362
 363 static inline unsigned long __copy_to_user_inatomic(void __user *to,
 364                 const void *from, unsigned long n)
 365 {
 366         if (__builtin_constant_p(n) && (n <= 8)) {
 367                 unsigned long ret = 1;
 368
 369                 switch (n) {
 370                 case 1:
 371                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 372                         break;
 373                 case 2:
 374                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 375                         break;
 376                 case 4:
 377                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 378                         break;
 379                 case 8:
 380                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 381                         break;
 382                 }
 383                 if (ret == 0)
 384                         return 0;
 385         }
 386
 387         check_object_size(from, n, true);
 388
 389         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 390 }
 391
 392 static inline unsigned long __copy_from_user(void *to,
 393                 const void __user *from, unsigned long size)
 394 {
 395         might_fault();
 396         return __copy_from_user_inatomic(to, from, size);
 397 }
 398
 399 static inline unsigned long __copy_to_user(void __user *to,
 400                 const void *from, unsigned long size)
 401 {
 402         might_fault();
 403         return __copy_to_user_inatomic(to, from, size);
 404 }
 405
 406 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 407
 408 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 409 {
 410         might_fault();
 411         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 412                 return __clear_user(addr, size);
 413         return size;
 414 }
 415
 416 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 417 extern __must_check long strlen_user(const char __user *str);
 418 extern __must_check long strnlen_user(const char __user *str, long n);
 419
 420 #endif  /* __ASSEMBLY__ */
 421 #endif /* __KERNEL__ */
 422
 423 #endif  /* _ARCH_POWERPC_UACCESS_H */